Snow physics:
Snow is a key actor in the Earth's climate system because it is the Earth's surface with the highest albedo. Snow albedo is determined by impurities such as black and brown carbon or mineral dust that absorb in the visible range of the solar spectrum, and by the size of snow grains, which determine light scattering at all wavelengths. To quantify light scattering by snow, the actual variable to consider is snow specific surface area (SSA), i.e. the snow crystal surface are by unit mass, expressed in m2 kg-1. We have pioneered novel methods to measure snow SSA, most recently based on infrared reflectance, and have built systems now manufactured under licence http://www.a2photonicsensors.com/medias/A2PS_IceCube_EN.pdf. Data are used for energy budgets and climate applications. Other studies of interest include the microphysics of snow metamorphism, and the study of the thermal conductivity of snow, which determines snow temperature and the heat flow between the ground and the atmosphere.Snow-climate-permafrost-vegetation interactions:
Snow impacts climate, but climatic conditions determine snow physical properties, so that there are snow climate feedbacks. Snow physical properties, and in particular its thermal conductivity, are also affected by the type of vegetation. Shrubs and trees protect snow from wind action, reducing its density and its thermal conductivity, so that snow in regions with high vegetation strongly insulates the ground. This limits winter ground cooling and accelerates permafrost thawing, so that there are complex feedbacks between snow, climate vegetation and permafrost that we are studying.Snow chemistry:
The amounts and types of impurities present in snow determine light absorption in the visible and therefore snow albedo. Besides particles of various types, absorbers include H2O2 and the nitrate ion, NO3-. Absorbing species can generate chemically active radicals such as OH, which initiate active photochemistry in the snowpack. This leads to the emission to the atmosphere of highly reactive species such as formaldehyde (HCHO), nitrogen oxides (NO + NO2) and halogens (Br2 and BrCl). These latter molecules start oxidation cycles in the polar atmosphere, that lead to high rates of mercury deposition and to rapid ozone destruction.

L.Chaix et F. Domine (1997) Effect of the thermal history of ice crushed at 77 K on its surface structure as determined by adsorption of CH4 at low surface coverage. Journal of Physical Chemistry B, 101, 6105-6108.